Self-leveling device for electric elevators



E. DRENKER April 5, 1938.

SELF LEVELING DEVICE FOR ELECTRIC ELEVATORS Filed Feb. 23, 1957 2 Sheets-Sheet l INVENTOR. EM/L v fiat/m6? April 5, 1938.

E. DRENKER SELF LEVELING DEVICE FOR ELECTRIC ELEVATORS Filed Feb. 23, 1937 2 Sheets-Sheet 2 ATTORNEY.

Patented Apr. 5 1938 UNITED STATES PATENT OFFICE SELF-LEVELING DEVICE FOR ELECTRIC ELEVATORS 1 Claim.

This invention relates to elevators and more particularly to such as use cars for the delivery of passengers and freight at selected landings.

Such cars, while under the control of an operator, frequently fail to come to a stop at the exact level of the landing, requiring restarting in one direction or the other in order to bring the floor of the car even with the floor of the building, necessitating delay and inconvenience, even with experienced operators.

It is therefore an object of the invention to provide an effective, electrically operated device which automatically causes an elevator car to come to a full stop when its floor arrives at a level with the floor of the landing, irrespective of the weight of its load.

A further feature is in the provision of a device which can be readily applied to elevators already in use, or to new installations, whereby a positive floor levelling effect is obtained.

These and other objects, which will become manifest as the description progresses, are attained by the novel and practical construction, combination and arrangement of parts hereinafter described and illustrated in the accompanying drawings, constituting a material component of this disclosure, and in which:-

Figure 1 is a partial side elevational, partial sectional View of an embodiment of the invention showing its structural features.

Figure 2 is a vertical sectional view taken on line 2-2 of Fig. 1.

Figure 3 is a diagrammatic view in front elevation of a conventional elevator and its guideway, showing an application of the device.

Figure 4 is a schematic view of the electric wiring system.

Referring in greater detail .to the drawings, Figure 3 shows the usual upright rigid runways l5 extending through the several floors and acting as guides for a car l6 having a platform 11 and crosshead l8 from which extend clips l9 to engage the runways l5.

Secured on the cross-head 18, at one end, is a plate to which is bolted a plate arm 2| having downturned lugs 22-23 drilled to receive a hinge pin 24 on which is mounted a hub 25, having upright and horizontal plate arms respectively 26-21.

An arm 28 extends from the lugs 22, opposite the arm 2| and is provided with an adjustable stop screw 29 .to limit the downward movement of the horizontal plate arm 21.

Raised from the lug 22 is a bracket 30 terminating in an elongated bearing 3| having a rotatable sleeve 32, in which is mounted a spindle 33, provided with collars 34-35 set-screwed thereto to prevent endwise movement.

A lever 38 is adjustably set screwed to the sleeve 32, between the end of the bearing and the collar 35, and a corresponding lever 40 is held on the extending end of the spindle 33.

Rotatably carried at the end of the lever 38 is a roll 39 and a similar roll 4| is mounted on the end of the lever 40. 10

Carried by a webbed portion 30 of the plate arm 26 are spaced members 43-45, rockingly mounted on the axis of the spindle 33, their lower portions being pressed outwardly by springs 44 set in the plate arm. 15

These members have fixed in them, in register with the springs 44, bolts passing through the lower elements 46 of levers 41-48, the lever 41 being set-screwed to the spindle 33 and the other lever 48 correspondingly secured to the sleeve 32. 0

The action of these levers is limited by reason of their ends 46 extending into a recess 49 and can be adjusted by nuts on the bolts.

The extreme upper ends of the levers 41-48 are provided with non-conducting bushings 50 25 through which slidably pass spindles 5| having contact heads 52-53 normally pressed outwardly by springs.

An upright plate 55, of non-conducting material, is bolted to an upstanding portion of the 30 plate arm 21 and carries, at its upper portion, contacts 51-58 connected by looped conductors.

The levers 41-48 are pressed outwardly to bring the contacts into engagement by compression springs set in recesses in the members 35 43-45.

In order to cushion and delay the movement of these levers, dash pot casings 62 are fixed on the rear side of the plate 55 and operable therein are plungers 63 pressed rearwardly by springs 64, controllable vents 65 being provided for the escape of air as the plungers are forced into the dash pots.

Stems 66, provided with flattened outer ends 61, containing slots 68, are passed through the plate 55 to abut the plungers, these stems being actuated by pins 69 set in the levers 41-43.

Mounted on the plate arm 2| is an electromagnet 1|] having an armature 1|, its outer extending end making operative contact with the horizontal plate arm 26 whereby the plate arms and elements associated with them are tilted on the axis 24.

Adjustably attached to car guide-ways, or other convenient adjacent points, are rigid cams 15-16, 55

the cam 15 being positioned to engage the roll 4| and the cam I6 to engage the roll 39, these cams being disposed on all floors except the extreme top and bottom.

Carried by the plate is a switch 11 controlling current tothe contact 51, a similar switch I8 controlling the contact 58, while a third intermediate switch 19, controls current to the electromagnet and is used when the levers are in neutral position.

Referring now to the wiring diagram, seen in Figure 4, an electric current enters the device by wire 80, passing through a fuse 8| to a switch 82, thence to the motor control arms 83--84 turnable on the axis 85 and carrying contacts one of which is connected to a conductor having amanually operable switch 9I and car-gate or door operated switch 92, the conductor eventually leading to the solenoid I0.

A branch of the conductor 90, is further branched, as at 9E-91, the former supplying current to the contact 53 the circuit between contacts 53 and 58 being automatically closed when the roll 39 is passed by the cam T6; the branch 91 conveys current to the contact 52 the circuit between contacts 52 and 51 being closed when roll 4| is passed by the cam I5.

Return current from the contact 58 is conducted by wire I00 to switch IOI, thence through solenoids I02I03 to switch I04.

A branch I05 of the wire I00 leads to a controller contact arm I06 contactable by the movable motor control arm 84 when a slow rate of speed is required in upward travel of the car.

A higher speed is obtained by moving the controller arm 84 further to engage another controller contact arm I0'I, connected by wire I08, passing through a solenoid I09, which weakens the shunt field of the car motor, and is joined. to a wire I I0 connecting the solenoids I02--I 03.

A branch III of the conductor I08 leads to a high speed controller contact arm II2 engageable by the movable motor control arm 83, adjacent to which is a slow speed contact arm II3, connected by wire II4 to the switch I04, while a branch II5 of the wire II4 leads to the car carried contact 51.

A wire IIB leads from the solenoid I09, provided with a switch I H, the wire being connected with a fuse H8 and leads to the main supply line.

A branch II9 of the wire H6 is provided with a switch I20 and leads to the solenoid I0, thereby completing the circuit.

In operation, when the car I6 is started in either direction, up or down, the door being closed, closing the switch 92 and retiring the rolls to avoid striking the cams on the floors to be passed.

When the car control lever is moved into neutral position, in order to make a stop on the desired floor, the electromagnet I0 will become energized, drawing the switch contacts into operative positions.

If the car moving up stops at too high a level, the up switch stays in oil position, while the down switch makes contact and brings the car to a level stop; in moving down the same effect is produced in a reverse manner. When the car door is opened the contacts carried by it break the circuit on the shunt line and the switches return to an off position.

Having thus described the invention and set forth the manner of its construction and application, what is claimed as new and sought to obtain by Letters Patent, is:-

In an electric elevator movable between fixed upright guide rails, said elevator comprising a car having a crosshead, a plate secured to said crosshead, an electromagnet on said plate having an axial armature disposed horizontally, an arm extending outwardly from said plate provided with an adjusting screw, a bracket having two arms disposed at a right angle pivoted in said plate, one of said arms in register with said armature and the other with said adjusting screw, a shaft journalled in said bracket, a sleeve circum jacent the shaft, levers fixed respectively on said shaft and sleeve, rolls rotatably mounted on the ends of said levers, cams fixed on said rails in register'with said rolls, resilient means to cushion the action of said levers when moved in either direction, spring actuated dash pots combined with said resilient means whereby said levers are cushioned near the limits of their movement, means actuated by said levers to control the elevator car motor, and selective control means for said electromagnet carried in said car.

EMIL DRENKER. 

